JP2000-16040 A discloses a suspension system for use in a vehicle, wherein a motor for driving the wheel is provided inside the wheel. With this arrangement, thanks to arranging the motor within the wheel, it is possible to make advantageous use of space within the wheel as well as to reduce the weight of a mechanism for transferring the driving power generated from the motor to the wheel.
In this conventional suspension system, since the motor is directly connected to the wheel, an unsprung mass increases by the amount of the motor and components associated therewith, resulting in a deterioration in a road holding characteristic and thus ride quality.